Automatic {13 {0 self contained {13 {0 light weight spreader bar

ABSTRACT

A container handling system which includes a generally rectangular spreader bar having hydraulic control means for the purpose of locking and unlocking corner attachments to the spreader frame.

I June 10, 1975 United States Patent IWI Durenec 294/67 R 4. 294/67 DA294/81 SF 3.428.354 2/1969 Grif'fith 3.501.193 3/1970 Gruy 3.712661[/1973 Strandm.v

3.767.250 10/1973 Ward l73| Assignec: The United States of America asPrimary Examiner-Even C. Blunk Assislunl Examiner-Johnny D. Cherry a ti.

an S en m HM Mm U nW Attorney. Agent. or Firm-Robert P. Gibson; NathanEdelberg Filed: Jan. 29, 1974 121 App]. No.: 437.566

ABSTRACT 294/82 SF: 294/67 DA Int. 1366c 1/66 n w f searchmmm 294 67 DA,A container handling system which includes a gener- 294/67 DB g[ 1 5 0 R7 ally rectangular spreader bar having hydraulic control means for thepurpose of locking and unlocking corner attachments to the spreaderframe [56l References Cited UNITED STATES PATENTS 4 Claims, 2 DrawlngFigures 2.847245 8/1958 294/110 R PATENTED H 0 I975 3.888.536

SE'IEEI 2 POWER SOURCE ACTUATOR AcTuAToR CLOSED OPEN 28 DELAY AND 24 24FLIP-FLOP A MATED 23 AND 25 AND 25 CLOSE OPEN AI TOMATK' SELF('UNTAINIQI) LIGHT WEIGHT SPREADER [HR The invention described llcl'clllmay he manufactured. used. and licensed by or for the government forgovernmental purposes without the payment to me of any royalties thereonBACKURUIND ()I 'I'Hl: INVENTION The present invention relates toequipment for lifting cargo containers by means of helicopters orvarious types of cranes such as a gantry crane. boom crane. straddlecrane or the likev In the past the cargo industry has employed\tll'ititts equipment often referred to as spreader frames or spreaderbars to transfer cargo from ship to shore or between ground locations.This equipment used with gantry cranes and boom cranes is constructed ofstruc tural steel which weighs from 1.5 tons for a manual fixed lengthunit to 7 tons for an adjustable length unit with retractable cornerguides and self-leveling systems. This high weight has made suchspreader bars incompatible with helicopter use. In addition. spreaderframes of the past have not had the rapid pickup and release necessaryto take full advantage of helicopter lift capability.

While some existing devices do connect cargo envelopes to a helicopter.they are designed and built to meet only a specific parameter.

SUMMARY OF THE INVENTION The primary object of the invention is toprovide a spreader bar assembly which is compatible with helicopter liftcharacteristics in general.

Another object of the invention is to provide a spreader bar assemblythat can be used with any crane. any aircraft, or even with a forkliftequipped with a hooking device having the required lifting capability.

Still another object of the invention is to provide an assembly which iscomparatively lightweight /2 ton). entirely self-contained and generatesits own energy source for operation A further object of the invention isto provide a spreader bar assembly which is fully automatic in itslocking and unlocking to the cargo container and which additionallyprovides a visual indication of whether the container is in a locked orunlocked condi tion.

BRIEF DESCRIPTION OF THE DRAWING The exact nature of the invention willbe readily apparent from a consideration of the following specificationrelating to the annexed drawings in which:

FIG. I is a perspective view of u spreader frame of the preferredembodiment of the in\cntion using single point suspension; and

FIG. 2 is a schematic diagram of the logic used in the automatichydraulic control system of the present invention.

DETAILED DESCRIPTION OF THI INVENTION Referring to Fl(i. I of thedrawing. there is shown spreader frame II which is suspended from asingle point by four carrying cables I2 which attach to the corners offrame II. l-ach of the carrying cables I2 is of s inch diameter teel. Ateach corner of spreader frame I I there is a t\\ ist lock I3 suitable toaccommodate the dimensional requirements of an 8 X 8 X It) (ill footcontainer. From the single point suspension. at fifth line e\tendsdownward. This line 14 is not a carrying line. but serves to activate anautomatic piston pump 15 which reacts to every slack of the activatorline. Any vertical movement of the line 14 generates energy andtransfers it to an accumulator 16. Any lifting movement reaching twofeet of stroke develops enough energy to operate all four twist locks I3thirty times full cycle. In addition. two of the four corners indiagonal location have a touch-down sensor I7. When both ofthe sensorsare in complete contact with the corner fittings of the container. asignal will be dispatched through the hydraulic system to logic 16 wherea flip-flop valve autt matically activates the hydraulic cylinder I8 andpasses the force through shaft I9 and push rod 20 to the twist locks 13with the assistance of the control valve 21 and reservoir 22. Thehydraulic system begins charging the instant the spreader bar assemblyis lifted because of the movement and its own weight by vertical motion.

The twist locks 13 have indicators painted green for open position andred for closed position, and are located in such a way that they arevisible to an aircraft operator. Two additional visual indicators arelocated on the long sides of the frame and have the same color coding.The indicators serve a dual purpose. They are employed as leveragecontrols for the manual override. and they also show the ground operatorthe actual position of the locks l3. Therefore. the safety and securityof the spreader assembly is protected by three controls: automatic,manual and manual/hydraulic.

In operation. the operator aligns the spreader assembly above thecontainer top and starts to lower the assembly. The twist locks I3 arein the open position and all indicators show green. Upon contact of thespreader assembly with the four corner fittings of the container. thetwo sensors 17 are compressed and send a signal to the logic 16 whichcauses the twist locks 13 to simultaneously close and the visualindicators to change to red.

During transport, the sensors I7 are not in contact with the cornerfittings. To prevent accidental sensor signals to the logic 16 whichcould be caused by vertical motion such as an air pocket or zero load.an adjustable built-in delay can be set from zero to five seconds. Uponarrival at destination and lowering. the spreader assembly must restuntil the delay time is reached. Only when the slings 12 have therequired slack will the twist locks 13 automatically open and theindicators turn green. Any vertical motion of the assembly charges thehydraulic system; therefore, energy not consumed is stored in the logicassembly 16 and the spreader is always ready for operation.

Referring now to FIG. 2, there is shown a logic diagram of theautomatiic control system. The realization of the diagram as actualhardware can be accomplished by electrical. pneumatic. or hydraulicmeans. In the preferred embodiment. hydraulic means was chosen becauseof simplicity. reliability and ruggedness. In such a system the elementsof the logic diagram take the form of hydraulic valves. The actuator I8is controlled by a three-way center-off valve with spring return to thecenter position. whose spool is actuated by a pilot cylinder in eachdirection. The OR gate 23 is a two-input shuttle valve permitting flowfrom either input to the output line. but preventing feedback from oneto the other. The two-input AND gates 24 are pilot actuated springreturn normally off valves. which supply no output pressure unless theyreceive input pressure at both the normal inlet part and the pilotcylinder. The multiple input AND gates 25 can be built up as assembliesof two or more such valves The sensors are mechanically actuateddirectional control valves with a spring return and toggle positioningmechanism. fitted for actuation by push rod. lever or cam followerroller as the mechanical design may dictate. The flip-flop element 26 ofthe logic design is a double pilot two position directional controlvalve with a toggle positioning mechanism that holds the control spoolin one open po sition until pressure is applied to the pilot cylinder onthat side and then snaps the spool over into the oppo site openposition. The inverting element 27 may be a two position pilot actuateddirectional control valve. The delay 28 is a small accumulator with oneor more flow restriction valves to control its rate of pressure build-upand drainv An additional pilot actuated control valve can be included asa comparator to insure that the delayed signal is generated when thepressure in the accumulator reaches a definite fraction of a referencepressure existing elsewhere in the system.

Although one embodiment of the invention has been shown and described.it will be understood that various modifications may be made withoutdeparting from the spirit and scope of the invention.

What is claimed is:

l. in a cargo container handling system. a spreader bar assemblyincluding:

a moveable support;

a rectangular frame with corner attachments connected to said support;

a hydraulic power source assembly embodying a hy draulic piston meansadapted such that selected movement of said piston means readies saidhydraulic power source assembly for operation;

hydraulic control means for locking and unlocking the corner attachmentsof the spreader frame. said hydraulic control means including safetyinterlock means disposed at each point of attachment and responsive tothe relative position of said spreader frame with respect to a cargocontainer. said control means adapted to lock and unlock corner attachments substantially simultaneously when a selected relativepositioning of said spreader frame with respect to a cargo containeroccurs and the spreader frame concurrently fully rests on the cargocontainer; and

means connecting said hydraulic piston means of said hydraulic powersource assembly to said move-able support such that a lift motion ofsaid move-able support, with said spreader frame resting on the cargocontainer and undisturbed by said lift motion. pressurizes saidhydraulic power source assembly.

2. The assembly of claim 1 wherein the moveable support includes asingle hook by which the spreader frame is supported and said meansconnecting said hydraulic piston means of said hydraulic power source tosaid moveable support is a relatively short cable means which isattached to said single book on said moveable support.

3. The assembly of claim 2 wherein said safety interlock means are loadresponsive means and include time delay means such that said safetyinterlock means react to a selected load less than the full weight ofsaid spreader frame when said safety interlock means is subjected tosaid selected load over a selected period of time.

4. The apparatus of cliam 3 further including means for visuallydetermining when said interlock means are secure.

k t a

1. In a cargo container handling system, a spreader bar assemblyincluding: a moveable support; a rectangular frame with cornerattachments connected to said support; a hydraulic power source assemblyembodying a hydraulic piston means adapted such that selected movementof said piston means readies said hydraulic power source assembly foroperation; hydraulic control means for locking and unlocking the cornerattachments of the spreader frame, said hydraulic control meansincluding safety interlock means disposed at each point of attachmentand responsive to the relative position of said spreader frame withrespect to a cargo container, said control means adapted to lock andunlock corner attachments substantially simultaneously when a selectedrelative positioning of said spreader frame with respect to a cargocontainer occurs and the spreader frame concurrently fully rests on thecargo container; and means connecting said hydraulic piston means ofsaid hydraulic power source assembly to said moveable support such thata lift motion of said moveable support, with said spreader frame restingon the cargo container and undisturbed by said lift motion, pressurizessaid hydraulic power source assembly.
 2. The assembly of claim 1 whereinthe moveable support includes a single hook by which the spreader frameis supported and said means connecting said hydraulic piston means ofsaid hydraulic power source to said moveable support is a relativelyshort cable means which is attached to said single hook on said moveablesupport.
 3. The assembly of claim 2 wherein said safety interlock meansare load responsive means and include time delay means such that saidsafety interlock means react to a selected load less than the fullweight of said spreader frame when said safety interlock means issubjected to said selected load over a selected period of time.
 4. Theapparatus of cliam 3 further including means for visually determiningwhen said interlock means are secure.